I bought a Malibu 300W low voltage landscape transformer to replace a 200W unit that stopped working. It worked for 1 week, then stopped .. the reset **** doen't work. The LED works, I do see a brown spot on the paper on the front panel that touches the transformer. Did it burn out?

Try connecting a lamp (correct voltage, etc) directly to the transformer. Most likely, the wire from the transformer to your lights is broken... The reset button can't reset anything, if there's nothing wrong there.

You can buy the Malibu Photocell Low Voltage sensor on eBay. Go to eBay and search "Malibu Photocell Sensor" and you should see it. Or search eBay item number 371829265599

Intermatic power pack has 5 year warranty, while malibu has 1 year warranty:
http://waterheatertimer.org/Malibu-power-pack-stopped-working.html
Open link above for installation tips and troubleshoot
Gene

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Hello jmanis

12 Volt AC
http://waterheatertimer.org/Malibu-power-pack-stopped-working.html

The bulbs for low voltage are labeled 12Vac

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

1) Copy following link for malibu power pack tips for longer transformer life:
http://waterheatertimer.org/Malibu-power-pack-stopped-working.html

2) Two plug choices on each outlet, Plug power pack into other outlet on receptacle.
Inspect for damage on outdoor outlet.
Replace outdoor outlet, and do not use quick connects. Connect wire directly to screws on side of device.
Replace GFCI outlet.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Check that power pack is getting electricity.
Power pack should make a small humming sound when on.
Scratch a wire across both terminal screws and see if there is spark.
If a bulb burns out, and is not replaced, additional voltage can burn out other bulbs.
Power pack should be unplugged if bulbs are not burning since that can burn out power pack.
Change out a couple bulbs and then plug-in power pack.
Check connections where lights tie into wire.

My power pack was doing same thing, I bought another power pack from Home Depot to check my lights. All but 2 bulbs were burned out. I replaced bulbs and returned new power pack.. and then power pack quit for good a month later.

I found tips to preserve power packs:
1) Match wattage of bulbs with wattage of power pack
-15 each X 20 watt bulbs = 300 watts, so install 300Watt power pack
2) Installing a 500W power pack on 300W of bulbs will burn out bulbs and power pack.
3) Replace bulbs as soon as they burn out or other bulbs will burn out and power pack will burn out.
4) When working on bulbs, unplug power pack or it may burn out.
http://www.malibulights.com/guides_support/low_voltage_planning_guide/select_your_power_pack

1) Contact malibu lights directly.
Their site does not acknowledge TDC PTST-30012, so I cannot access a manual with best information.
Their products come with a warranty.
http://malibulights.com/customer_service/contact_us.aspx
http://malibulights.com/customer_service/owners_manuals.aspx

2) If unit can be set to override, you can buy cheap photo eye timer, and then plug power pack into cheap timer, but there is no guarantee this will work, or that power pack will burn out.
http://www.amazon.com/Intermatic-HB61RC-Digital-Outdoor-Control/dp/B00004W4X5

3) Buy ordinary power pack with dial-type timer, and then buy photo eye that fits.
http://www.intermatic.com/products/professional%20lighting/light%20expressions/accessories/ml814drp.aspx

http://store.nexternal.com/intermatic/categories.aspx?Keyword=ML814DRP&x=15&y=10

4) As electrician, I would not buy anything that costs more than $15 that comes with built-in photo eye that cannot be replaced.
Especially something as buggy as a low voltage power pack.
http://waterheatertimer.org/Malibu-power-pack-stopped-working.html

There are no repair parts for intermatic/malibu power packs.
If problem timer malfunction, then set power pack to override, buy cheap plug-in timer, and plug power pack into cheap timer.
If problem is internal wiring, then replacement is option.

For more information on Intermatic/Malibu power packs showing troubleshoot steps, replacement trippers, useful links, warranties and tips:
http://waterheatertimer.org/Malibu-power-pack-stopped-working.html

bulbs or wiring

Testing ohms across A and B will read open circuit through transformer coil.
Testing DC voltage across terminals A and B should read 12 volts DC, and nothing less.
Transformer should make humming sound when working.
Test that receptacle has power and breaker is not tripped.

There are no repair parts for power packs, but they come with 5 year limited warranty.

For more information on Intermatic/Malibu power packs showing troubleshoot steps, replacement trippers, useful links, warranties and tips:
http://waterheatertimer.org/Malibu-power-pack-stopped-working.html